Embedded Programing

COUNTDOWN

Embedded Programing

Assignments

For this week we had two assignment:

• Individual Assignment:
• Read a microcontroller datasheet.
• and program my board to do something with as many languages.
• Group Assignment:
• Compare performance and development workflow for other architectures.

Individual Assignment

Before starting anything, I had to read the datasheet of the microcontroller I would be using so I can base my design accordingly. The one I was to use was the ATtiny44, the Datasheet would have a detailed explanation of all the components and possibilities of this microcontroller as well as the specs and dimensions that would be used in designing the PCB. It also explains the functions that it could handle and provide as well as some code examples. Also the limitations of the ATtiny44 are explained. Below are some of the information I want to highlight would be considered essentials for the task at hand.

• First and foremost the Pinouts of the microcontroller to be able to design accordingly and know where to add the needed components.





• The clock is important as it will give the PCB a notion of time and allow the micriocontroller to go through timed cycles. Here is a diagram on how the clock should be linked to the ATtiny44.





• The datasheet also explains the different ways this microcontroller can be programmed. As we would be using an ISP serial programming the image below taken from the datasheet shows the pins needed for that process.





• And another important piece of information are the absolute maximum ratings this specific microcontroller can handle as in voltage, current and temperature.

Programing with the Arduino:

1. First we need to connect the Arduino to the PC
2. Then we need to download the Microcontroller file in boad manager, (Attiny44) in this case.





3. Then select the board the tool tab.





4. Select which Attiny Processor. (Attiny 44)





5. Select the Clock (Crystal SMD Frequency, 20 Mhz in this case)





6. Now under tools, select Arduino as ISP in order to program our new PCB





7. Now under examples, we need to upload the ISP code to the Arduino





8. Now that the Arduino is serving as an ISP, it is time to connect our PCB to the Arduino
• The connections are as follows:
  
  GND to GND
  
  VCC to 5V
  
  SCK to pin13
  
  MOSI to pin11
  
  MISO to pin12
  
  RST to pin10
  





• And the plug the Arduino back to the PC
9. Now under the tools tab, Burn Bootloader





10. Now it is time to write the code on the Arduino IDEthat the the PCB is going to execute.




int LED= 7; int BTN= 3; int ButtonState= 0; int ButtonCount= 0; int ButtonLast= 0; void setup() { // put your setup code here, to run once: pinMode (LED, OUTPUT); pinMode (BTN, INPUT); } void loop() { // put your main code here, to run repeatedly: ButtonState= digitalRead(BTN); if (ButtonState == HIGH) { delay(200); ButtonState= digitalRead(BTN); if (ButtonState == HIGH) { digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(300); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); }else if (ButtonState == LOW) {digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(300); digitalWrite (LED, LOW); delay(150); digitalWrite (LED, HIGH); delay(100); digitalWrite (LED, LOW); delay(150); } } }





11. I have deigned this code to do two similar tasks based on the input. Since it is my first time programming an arduino I went with something simple and basic yet made the most out of it. Since I had one Button and one LED, I made the LED to flash different Morse codes.
• If the button is pressed once the LED will turn on and flash the Letter "G" in Morse code
• If the button is pressed twice within a frame of 200ms, the LED will turn on and flash the word "FabAcademy" in Morse code





12. Then Check the Code and Upload it to the PCB through the Arduino Software





13. Upload the code using the 'Upload using programmer' tool under 'Sketch'





14. Once everything is set you could just plug in the VCC and the GND and your PCB is ready

Programing with the C-Language:

1. First we need to create the C-file, this code can either be written and uploaded through the Arduino, or could be written in a text file and uploaded through the FabISP through the terminal on Lynux where the latter is the case shown below
• The Connections go as show in the picture below:





2. There are 4 crucial files that are needed in every C-code program flashing and they are as follows
• First you need your C-code written and save in a '.c' format




/* Including Libraries * Defining pins * int main (void) { * setup * loop --> while (1) { * } * } */ #include <avr/io.h> #include <util/delay.h> //define frequency of the mcu #define F_CPU 20000000UL int main (void) { //0-->input //1-->output //PA7-->Led //PA3-->Button DDRA = 0b10000000; while(1){ if (bit_is_clear(PINA, PA3)){ PORTA = 0b00000000; } else { //for (int i = 0; i<25; i++){ PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(300); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(100); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); PORTA = 0b00000000; _delay_ms(150); PORTA = 0b10000000; _delay_ms(300); } } }





3. Now you need to install the necessary libraries through the Lynux terminal and install them, shown below


sudo abt-get install flex byacc bison gcc libusb-dev avrdude

sudo apt-get install gcc-avr

sudo apt-get install avr-libc

sudo apt-get install libc6-dev




4. Next you need the MakeFile



• The Make file is basically the mediator between the Processor and the code written on the PC. The image below shows the contents of the MakeFile, it has a variety of executable codes once it determines the best for the connected processor. (This makefile was acquired from the fab archives, link found on the bottom of this page).



• Make File screenshot:





• The rest once you have the file, all the rest is on the Lynux terminal and using the MakeFile is as shown below





5. Next you need the Hex File
• In order to use the hex file, you first have to access the directory of the makefile itself. and then use the below command to create it, and it goes as shown below.


make (name of your C code file).hex




6. Next you need the Out File
• And then going with this order, the last file needed is the OUT file and is shown below.


make (name of your C code file).out




7. And finally type in the command 'make program-usbtiny' and the program is uploaded onto the PCB

Group Assignment

When it comes to comparing the performance and development workflow of the different approaches one can take to program a PCB, there are a lot of factors that should be taken into consideration. I cannot say for all but as for the ones I used here is my assessment and comparison:

• Arduino-Code
• When it comes to programming, especially someone new to this, Arduino is the most straight forward approach to program a PCB, the fact that it could be considered as a 'joker' as in you can use it as an ISP.
• The code that is written for the arduino is also basic as it encapsulates C-code in more userfriendly functions and terms that make it easier and more efficient to execute any desired code.
• The backdraw of using the Arduino code is that since it is considered user friendly, is that it really is the most 'on the surface' code someone can use. Although it is true that it is a great way to start and one can achieve many milestones with it, more complex processes might require other codes.
• C-Code
• C-code is the most basic coding language, it can be applied and implemented to most of micro-processors. It is not as simple as Arduino-code but at the same time it is somewhat logical. without the Arduino IDE, C-code could be uploaded to an ISP and processor through the terminal on Lynux with the steps shown above.
• C-code is pretty straight forward and closer to the 'end product' which is the binary code. as in when you want to specify a pin, instead of saying ex: PIN 11. You need to first specify the PORT as in A or B and it goes on depending on the microprocessor capacity and size. Then each PORT is comprized of 8 pins starting from 0 all the way to 7. And then each pin's function is specified as input or output, 0 or 1. so if you want to use Pin 2 as an output and the rest are inputs, you would have to set is as PORTA = 0b00100000. Then you go again and set each pin when you want to use it. It is somewhat confusing because you are using the same letters for different functions with different uses.
• Even though I am not use C-code for my future projects, it was important to get to know the basics of C and the uses of it. I think it is crucial to understand C to set the basis for other coding languages.
• Python-Code
• Based on my experience, I only used the Python-code on Raspberry Pi 3, and on the Rasperian Operating system to be specific. It is my first experience with this and it is just great. The fact that I am 'inside' the microprocessor, having a very user friendly and efficient operation system as in only have the most basic functions that one might use, it is amazing. I am sure more experienced users would find a lot of downsides for it but so far I like it and it really was, in my humble opinion, the most efficient
• I like to take it as biomimicry as in the processor is the brain and all connected circuits are extensions of this nervous systems. Being inside that processor and be able to execute any Python code and run it on the circuits with a command or pressign F5 is incredible. Instead of having to go through all the wiring and additional extensions. So it is basically an all in one for basic projects, but we all know these have downsides I just havent figured them out yet.
• The Python-code and uploading goes as follows:





• And thats it, you write the code and run it. It also have a screen that displays errors where you would easily pinpoint the source of any bug.
• As for the Python code itself, it also is almost as basic as Arduino it just uses different functions and different approaches to achieve the desired outputs.
• I learned through simple tutorials with basic searches on the web. Although there is always more that one way to achieve the desired output, it comes down to a matter of the most efficient one.
• The code I used was basically a push button and 6 LEDs and had the LEDs flash quickly in a circular pattern and run the loop for any specified amount of times. The code is found below:




import RPi.GPIO as GPIO from time import sleep GPIO.setwarnings(False) GPIO.setmode(GPIO.BOARD) GPIO.setup(8, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(10, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(12, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(16, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(18, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(3, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) i=0 while True: if GPIO.input(24) == GPIO.HIGH: while i<100: GPIO.output(8, GPIO.HIGH) sleep(.01) GPIO.output(8, GPIO.LOW) sleep(.01) GPIO.output(10, GPIO.HIGH) sleep(.01) GPIO.output(10, GPIO.LOW) sleep(.01) GPIO.output(12, GPIO.HIGH) sleep(.01) GPIO.output(12, GPIO.LOW) sleep(.01) GPIO.output(16, GPIO.HIGH) sleep(.01) GPIO.output(16, GPIO.LOW) sleep(.01) GPIO.output(18, GPIO.HIGH) sleep(.01) GPIO.output (18, GPIO.LOW) sleep(.01) GPIO.output(3, GPIO.HIGH) sleep(.01) GPIO.output(3, GPIO.LOW) sleep(.01) i+=1





• I could also add that Python sort of forces you to keep your command line in order as in it goes in in hierarichal order. Wich is something fairly important to keep in mind and take into consideration when writing any sort of code. Maybe not for the time being but for future references and when trying to go back to it for any adjustments and way easier for debugging.
• Here is a short video of the result using Raspberry Pi:

Downloads